Who owns the knowledge your community produces?

When a Wikipedia editor writes an article, who owns that text? When a Reddit community collectively develops a wiki, who holds the copyright? When an open-source project releases code under a permissive license, who controls the downstream derivatives? The commons problem is well-studied in land and water. But knowledge commons operate by different rules: it can be copied without depletion, shared without loss, and built upon without diminishing the original. Yet communities still face the question of stewardship — who gets to decide how knowledge evolves, who can gatekeep contributions, and what happens when a commons becomes extractive? Consider: if a corporation scrapes your community's curated database to train a commercial AI, do you have any recourse? Is "open access" enough, or do communities need stronger governance structures over their knowledge production?